The invention relates to thrust reversing of aircraft gases and more specifically to the reversing of fan gases of a turbofan engine.
Various difficult types of fan gas reversers presently exist, most of which are considered to be useful for their intended purpose. Some of the prior art reversers utilize cowl section translation with simultaneous deployment of reverser or blocker doors, as well as providing an opening in the cowl surrounding the turbofan engine with a translatable cascade ring being positioned therein to provide an exit and direct the gases forwardly through.
Actuation mechanisms generally consist of links and linear actuator means for both cowl section translation and reverser or blocker deployment. A novel two-part reverser or blocker door is taught by U.S. Pat. Nos. 3,964,257 and 4,073,440, wherein the abutting ends of the reverser or blocker doors form curved single rack gears with interlocking and meshing teeth so that both reverser or blocker door operate simultaneously between their stowed and deployed positions. A clam shell type thrust reversing mechanism having curved single rack gear abutting ends on each claim shell for simultaneous movement between their stowed and deployed positions are taught in U.S. Pat. No. 3,759,467.
As aforementioned, most of the existing thrust reversing mechanisms have various merits and in most instances have been used with some degree of success. The principle objections have included requirements for excessive operating mechanism to insure uniform reverser or blocker door deployment that results in excess weight, which is critical in aircraft, higher economic costs and complexity with the resulting high maintenance both in down time and cost, and very little of any consideration of design was directed toward maintaining excess area size balance during the deployment of the reverser or blocker doors to prevent the possible loading or stalling of the engine (through back pressure).